Processing systems such as computers may include different types of subsystems that can be accessed at different speeds. For example, solid state memory devices may be accessed faster than mass storage devices such as hard disk drives. Some types of memory may be used to cache information that is read from a hard disk drive. Accessing data to be read (“read data”) from or to be written (“write data”) to a cache memory is generally faster than accessing the same data on a hard disk drive, and so many systems include hard disk cache memory.
Platform-based disk caches are disk caches physically outside the disk(s). On systems with platform-based disk caches, I/O to the cached disk may be requested while the disk cache is inaccessible. Data integrity is a concern when performing I/O during such periods of disk cache inaccessibility.